As a background-art push switch, there is a switch operation device which is mounted in a vehicle in use and operated to be pushed from the outside (Patent Document 1). As shown in FIG. 7, this switch operation device is provided with a switch 103 having a movable portion 102 and soldered and fixed onto a circuit board 101, a casing 105 having an opening hole 104 and disposed in front of the switch 103, and a push button 106 attached to the casing 105 at a circumferential edge of the opening hole 104 so as to close the opening hole 104.
This push button 106 is made from synthetic rubber with flexibility and has an attachment portion 109 which is attached to the circumferential edge of the opening hole 104, a pressing operation portion 110, a thin flexible portion 111 which connects the pressing operation portion 110 with the attachment portion 109, and a shaft portion 112 which can move the movable portion 102 of the switch 103 due to the pressing of the pressing operation portion 110. The push button 106 makes the inside of the casing 105 watertight. To operate this switch operation device, the pressing operation portion 110 of the push button 106 is pressed or released from pressing in the illustrated up/down direction so as to turn on/off the switch 103.
However, in the aforementioned push switch, because the push button is made from a soft material, there is a fear that the push button may be cracked or broken if the push button is hit by something hard such as a nail when the push button is pushed by a finger or the like. In addition, the whole pressing force of an operator acts on the switch when the operator operates the push button of the push switch. Thus, there is a fear that the switch may be damaged if an excessive pressing force is applied to the push button of the push switch.
Further, when the pushbutton of the push switch is operated, the push button is not always pushed only from the illustrated up/down direction, but there is possibility that the push button may be pushed from any direction. When, for example, the push button is pushed from an illustrated obliquely lateral direction, there is a fear that a lower end of the shaft portion of the push button may move horizontally due to a certain way of the operator's pressing so that the pressing force cannot be applied to the switch correctly.